Install gnustep-core-doc by entering the following commands in the terminal:
sudo apt update sudo apt install gnustep-core-doc
Description:
GNUstep Development Environment -- core documentation
These packages provide documentation for developing programs for the GNUstep environment. . This is a metapackage that depends on the documentation packages of the core GNUstep development environment (GNUstep Make, Base and GUI).
Homepage: http://gnustep.org
Version: 7.9
Section: universe/x11